How accurately can river height, width, slope, and discharge be estimated from ideal SWOT outputs?
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Date
2013-12
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Publisher
The Ohio State University
Abstract
The proposed SWOT (Surface Water and Ocean Topography) mission is intended to produce, for the first time, global estimates of surface water storage change and discharge. With many advancements in remote sensing NASA is planning for this satellite to produce data products of high accuracy. In order to estimate the actual performance of the SWOT satellite a simulator was developed by NASA scientists at the Jet Propulsion Laboratory to produce SWOT outputs given specific inputs.
This study simulated SWOT observations over a study reach along the Sacramento River in California. The instrument simulator produces a cloud of point measurements of the river. Four methods of calculating reach-averaged river height, width, and slope from the point cloud data were explored. Errors in surface water height, width, and slope were characterized. These measurements are well within the science requirements. These values were used to estimate reach-averaged discharge along the study area, and calculated discharges were compared to modeled discharges to assess accuracy. Discharge mean absolute error values ranged from 6.6 % - 16.5 % depending on the method used to calculate SWOT measurements from the point cloud. Errors in calculating river discharge will be more heavily dependent on nontechnical factors rather than instrument capability.
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Keywords
SWOT, HEC-RAS to ArcGIS, Remote sensing of river discharge, manning's equation